Chip card device for transmitting digital information using acoustic means

ABSTRACT

A device for transmitting information by acoustic means, the device being constituted by a smart card of standardized format incorporating at least one microcircuit for generating signals for directly exciting a sound transducer, and an independent complementary unit, wherein said unit incorporates at least one smart card connector, an electric battery for providing electrical power to the microcircuit of the smart card, and the sound transducer for emitting the excitation signals transmitted by said smart card.

The present invention relates to a smart card device for transmittingdigital information by acoustic means, e.g. to a remote server forauthentication purposes and via a telephone or the microphone of amultimedia microcomputer.

BACKGROUND OF THE INVENTION

Various devices are known that emit authentication informationacoustically, and in particular cordless units, various cards,optionally of International Standards Organization (ISO) format,incorporating sound-production means, generally a lithium battery, and apiezoelectric ceramic disk, or indeed cordless readers entirelyanalogous to conventional smart card readers but communicating with theoutside not by cable but by acoustic modem.

Each of those devices presents drawbacks:

-   -   cordless units do not come within the context of smart card        industry, and as a result they do not benefit from the        performance of production tools (costs, personalization        services, management procedures), nor do they benefit from a        format that is recognized worldwide for payment or credit cards.        In addition, those units are not compatible with existing smart        cards;    -   ISO format cards that include acoustic transmission means are        difficult to manufacture, fragile, and expensive; and    -   readers with an acoustic modem need to carry the software        required for processing cards, and as a result they are        expensive and not very flexible, and in addition it is difficult        to encourage a large part of the public to adopt use thereof.

OBJECTS AND SUMMARY OF THE INVENTION

The device of the present invention relies on concepts that remedy themain drawbacks of those techniques. According to first characteristic,the device comprises a smart card and a complementary unit, e.g. in theform of a case into which the smart card can be inserted. According to asecond characteristic of the device, the smart card incorporateselectronic means for generating signals for exciting a sound transducer,the complementary unit incorporates at least one sound transducer and abattery necessary for supplying electrical energy. Without it beingessential for operation of the device of the invention, the unit mayinclude an activation button to trigger sound emission by the device;such triggering could alternatively be consecutive to the card beinginserted in the unit. The smart card and the unit are interconnected viaa standardized connector for smart cards. In particular, the transducerexcitation signals pass via unallocated contact points C₄ and C₈ definedby ISO standard 7816. When the smart card is inserted, its electroniccomponent is powered by the unit via standardized contacts C₆ (alsoreferred to in the standard as VPP), and C₅ (GND). Informationconcerning activation of the key is transmitted via contact C₂ (RST)which is connected to a chip input signal with pull-up, the referencevoltage being the ground contact C₅ (GND).

According to an important advantage of the invention, the electricalcontacts between the smart card and the complementary unit do not in anyway harm compatibility between the smart card and other environments,and in particular with known uses for standard smart card readers.

A second important advantage of the device of the invention is that thesmart card is in fact dissociated from the complementary unit. Thus, thefunction of emitting information acoustically can be provided solely atthe time when it is needed, for example, when performing a check in anapplication of the smart card as an identity (ID) card. Since the mainpart of the extra cost of the acoustic interface lies in integrating thebattery and the transducer, this extra cost is not borne by each cardthat is issued.

A variant of the invention consists in fitting the complementary unitwith a keypad and giving the smart card additional communications meansenabling it to read the state of the keypad, i.e. the references of thekeys that have been pressed. When a card is inserted in the unit, a keypress is detected by means of an integrated circuit incorporated in theunit, and electrically powered by the battery. The integrated circuit isprovided with a communications interface enabling it to use a singlesignal to inform the smart card of any change in the state of thekeypad, and to transmit the state of the keypad to the smart card onrequest.

Under such circumstances, the controlling integrated circuit of thekeypad is slaved to the smart card, with information being transmittedconventionally via a synchronous type serial communications busconstituted by a clock signal and a data signal. Once a key press hasbeen detected, the circuit informs the smart card of a change in thestate in the keypad, and the smart card can then decide to read the newstate by sending a read command to the integrated circuit controllingthe keypad via the available serial communications bus.

Advantageously, the keypad can be used to present a secret code to thesmart card that is known only to the user and that is used, for example,as a complement to authenticating the card in order to verify theidentity of its bearer.

The ease of use of the device can advantageously take advantage of thepresence of the sound-generating means for assisting the user ininputting the code, and for indicating that the code has been taken intoaccount.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, given by way of example, illustrate theinvention:

FIG. 1 is a diagrammatic transparent view of the device of the inventioncomprising the smart card and the complementary unit in which the cardcan be inserted;

FIG. 2 shows a variant of the device in which the smart card includesanother variant of the device in which the complementary unit is notprovided with a keypad; and

FIG. 3 shows another variant of the device in which the complementaryunit is provided with a keypad.

MORE DETAILED DESCRIPTION

In a first particular embodiment of the invention as shown in FIG. 1,the smart card 10 includes a microcircuit M having a standardized powersupply and communications interface I using contacts. The microcircuit Moperates in two modes: a first mode known as “slave” mode when the smartcard 10 is inserted in a smart card reader; and a second mode known as“independent” mode when the card is inserted in a complementary unit 11of the device of the invention. The complementary unit 11 includes atleast one connector C having contacts suitable for co-operating with theinterface I of the card 10, an activation key B, a battery P, and asound transducer T.

When the microcircuit M operates in slave mode, electrical power isconventionally supplied by the smart card reader via contact points C₁(VCC) and C₅ (GND). Communication between the microcircuit M of the cardand the reader is provided by the two-way signal C₇ (I/O), the drivingclock being C₃ (CLK). In this embodiment, the microcircuit M is providedwith an internal reset signal, automatically operated by being switchedon. The signal RST (C₂) is therefore not used in the slave mode ofoperation. Operation of the smart card 10 of the device of the inventionin this mode is well known to the person skilled in the art since it isin compliance with ISO standard 7816. This mode is used in particular topersonalize the microcircuit M during the process of manufacturing theproduct.

When the microcircuit M is operating in independent mode, its electricalpower is supplied by the battery P of the complementary unit 11 of thedevice of the invention via the contact points of the connector Ccorresponding to C₆ (VPP in the standard) and C₅ (GND), contact point C₆being connected to the power supply input VBB of the microcircuit M.Contact C₂ (RST) is connected to the activation key B by providing aconnection to ground C₅ (GND) on being pressed by a finger, thecorresponding signal at the microcircuit M being referenced DECL. When achange in the logic state of the signal DECL is detected by themicrocircuit M, it triggers acoustic emission by generating signaltrains for exciting the sound transducer T of the complementary unit 11.These signals generated by the microcircuit and referred to as T₁ and T₂are transmitted to the sound transducer T via the contact points of theconnector C that correspond to C₄ and C₈.

The sound produced by the microcircuit M conveys digital information,e.g. for the purpose of authenticating the card. It is demodulated bysignal processor means which transform the analog sound signal intodigital information.

In a second particular embodiment of the invention as shown in FIG. 2,the complementary unit 11 of the device of the invention remainsidentical to that described for the first embodiment, and the smart card10 reproduces the same principles as specified for the first embodiment.It further includes a second microcircuit M₂ for the smart card which isconnected to the communications and power supply interface I.Conventional microcircuits for smart cards, e.g. for bank cards, makeuse essentially of five out of the eight points of the interface definedby the standards: C₁ (VCC), C₂ (RST), C₃ (CLK), C₅ (GND), and C₇ (I/O);their communications protocol with readers is of the asynchronous type.

The two circuits in this embodiment of the invention are connectedtogether in parallel with the interface I. The device of the inventionmakes this possible since VCC and GND are common to both microcircuits Mand M₂. Given the low electrical power consumption of the electroniccomponents, this does not lead to any problem with the reader which isrequired by the standard to be capable of delivering electricity atlevels much greater than those consumed by the two microcircuits.

The microcircuits of present-day smart cards no longer make use of thesignal C₆ which was previously used as a programming voltage in memorytechnologies that have become obsolete. In a standardized procedure,readers are required to maintain this signal at 0 volts on request ofthe card. The microcircuit M that performs acoustic modulation cantherefore occupy the contact C₆ without leading to disturbance for itsown power supply in the independent mode described for the precedingembodiment.

Cohabitation between the signals C₂ (RST), C₃ (CLK), and C₇ (I/O) doesnot lead to problems since the signals are either input signals orsignals that are subject to the use of internal pull-up resistorsenabling them to be connected in parallel, and since the communicationsprotocols are different (synchronous/asynchronous), communicationbetween a reader and either particular one of the microcircuits will beignored by the other microcircuit, and vice versa. Furthermore, sincethe contact points C₄ and C₆ are not allocated by the standard forasynchronous type microcircuits, they are free for use by themicrocircuit M.

This embodiment of the invention is useful for adding an additionalapplication, namely the ability to transmit information acoustically, toa card that is already being distributed without this ability. Forexample, it is possible to add the function of authenticating the cardby recognizing the acoustic sequence in a server to a bank card of akind that already has a chip.

In a third particular embodiment of the invention (not shown), thecomplementary unit of the device of the invention remains identical tothat described in the first two embodiments, and the smart cardreproduces overall the principles set out for the first two embodiments,however it has a single microcircuit in the smart card connected to thecommunications and power supply interface. This microcircuit comprisescombining the two microcircuits M and M₂ of the second embodiment into asingle microcircuit.

In a fourth particular embodiment of the invention as shown in FIG. 3,the complementary unit 11 includes a keypad K and an integrated circuitG for controlling the keypad. When the smart card 10 is inserted in thecomplementary unit 11, if a key of the keypad K is pressed, then theintegrated circuit G detects a change in the state of the keypad andinforms the smart card by activating the signal corresponding to pointC₂ of the interface I. The smart card 10 can then launch a procedure forreading the state of the keypad K over the communications busconstituted by the signals CLK and I/O connected to the integratedcircuit G via the points C₃ and C₇ of the interface I. The keypad 10 maycomprise, in particular, ten keys corresponding to the ten digits, plusan eleventh key corresponding to the command for triggering soundemission.

In each of the embodiments, industrial implementation of the deviceconsists firstly in making a standard smart card whose micromoduleincorporates the microcircuit(s) as described, and secondly in making acomplementary unit including a smart card insertion slot. The unitincorporates a battery, a sound transducer, and an activation key, andmay be in the form of an object having approximate dimensions of 60millimeters (mm) in length, 30 mm in width, and 7 mm in thickness. Theunit may also be provided with a fastener system enabling it to be usedas a key ring.

1. A device for transmitting information by acoustic means, the devicebeing constituted by a smart card of standardized format incorporatingat least one microcircuit for generating signals for directly exciting asound transducer, and an independent complementary unit, wherein saidunit incorporates at least one smart card connector, an electric batteryfor providing electrical power to the microcircuit of the smart card,and the sound transducer for emitting the excitation signals transmittedby said smart card.
 2. A device according to claim 1, in which theelectrical excitation signals for the transducer leaving themicrocircuit of the smart card correspond to contact points C₄ and C₈ ofa communications and power supply interface as defined by ISO standard7816.
 3. A device according to claim 1, in which the complementary unitincludes an activation key for causing the smart card to generate thesignals for exciting the sound transducer of said unit.
 4. A deviceaccording to claim 1, in which the complementary unit incorporates akeypad and an integrated circuit controlling the keypad.
 5. A deviceaccording to claim 1, in which the complementary unit is in the form ofan object having length of about 60 mm, width of about 30 mm, andthickness of about 7 mm.